Multiple piston for internalcombustion engines



Jan. 4, 1949. R. SOLTESZ 2,458,111

MULTIPLE PISTON FOR INTERNAL-COMBUSTION ENGINES Filed Feb. 11, 1947 2Sheets-Sheet 1 RUDOLPH SOLTESZ INVENTOIL,

BY 8on6. V/01M nrroklve-Y Jan. 4, 1949. SQLTESZ 2,458,111

MULTIPLE PISTON FOR INTERNAL-COMBUSTION ENGINES Filed Feb. 11, 1947 2Sheets-Sheet 2 START OF START OF END OF INTAKE STROKE COMPRESSION STROKEcommasaou STROKE POWER STROKE EXHAUST S ROKE MIDPOINT OF COMPRESSIONSTROKE RUDOL PH SOL TE 52 IN V EN TOR.

ATTORNEY Patented Jan. 4, 1949 UNITED STATES PATENT OFFWE MULTiPLEPISTON FOR mam].-

COMBUSTION enemas Rudolph Soltesz, Wheeling, W. Va.

Application February 11, 1947, Serial No. 727,903

Claims. 1

This invention relates to internal combustion -engines and moreparticularly to engines of this type having a sleeve piston and an innerpiston adapted to move within the sleeve piston.

There have been numerous attempts to improve the efiiciency of internalcombustion engines, many of which have comprised efforts to increase thecompression pressure of the engine by introducing larger volumes of airinto the cylinder during the intake stroke. Such efforts have ordinarilynecessitated increasing the cylinder bore or lengthening the stroke,both of which expedients are undesirable. In recent years the art hasrelied upon the use of superchargers to accomplish the desired result.The weight of superchargers imposes serious limitations upon theapplication of these devices and their use is not always practical.Furthermore, the cost of a supercharger makes it an expensive adjunct toan internal combustion engine.

The foregoing objections are overcome by this invention which, brieflystated, comprises pro-' viding an internal combustion engine with a mainsleeve piston and an inner piston adapted to move within the main sleevepiston. During the intake stroke the main sleeve piston moves downwardlyin the conventional manner while the inner piston moves downwardlywithin the main sleeve piston at about twice the speed of the latter. Atthe completion of the intake stroke, the inner piston is positionedbelow the uppermost horizontal surface of the main sleeve piston withthe result that the volume in the cylinder above the pistons isapproximately one-third greater than if both pistons had moved as aunit. During the compression stroke the main sleeve piston movesupwardly in the usual manner while the inner piston moves upwardly atabout twice the speed of the main sleeve piston. At the completion ofthe compression stroke the uppermost horizontal surfaces of both themain sleeve piston and the inner piston coincide or fall in the sameplane to provide a continuous piston head surface. In this position theinner piston forms a head for the main sleeve piston and thisrelationship remains fixed during the power and exhaust strokes. Thus.during the power and exhaust strokes there is no relative movementbetween the main sleeve piston and the inner piston. The foregoingoperation introduces approximately one-third greater volume of air intothe cylinder during the intake stroke which increases the compression,improves the emciency of the engine and provides other advantages awell.

It is the principal object of this invention to increase the compressionof an internal combustion engine and to maintain the increased pressurethroughout the power and exhaust strokes.

Another object of this invention is to provide an internal combustionengine having a main sleeve piston and an inner piston which arerelatively movable and adapted to increase the compression of the engineby introducing a large volume of air into the cylinder duringthe intakestroke.

Still another object of this invention is to provide an internalcombustion engine having relatively movable inner and outer pistonsadapted to afiord improved cooling of the piston surfaces during engineoperation.

A further object of this invention is to provide an internal combustionenginehaving relatively movable inner and outer pistons adapted toincrease the compression of the engine by increasing the operatingpressure of the engine throughout the power and exhaust strokes andafford improved exhausting of waste gases.

A still further object of this invention is to provide an internalcombustion engine in which the uppermost end of the combustion chamberand the head of the piston are curved to aflford increased turbulence ofthe combustible gases in cylinder.

It is also an object of this invention to provide an internal combustionengine having a main sleeve piston and inner piston which move withrespect to each other during theintake and compression strokes to affordhigh compression and which remain immovable with respect to each otherduring the power and exhaust strokes to maintain the increased pressure.

Other objects and advantages will appear from the following descriptionand the drawings in which:

Fig. 1 is a side elevational view partly in crosssection of an internalcombustion engine embodying the invention;

Fig. 1a is a detailed plan view of the rocker arm catch;

Fig. .2 is a vertical sectional view taken on line 2-2 of Fig. 1;

Figs. 3 to 7 are diagrammatic views showing main sleeve piston and innerpiston positions at a series of successive points in the engine cycle;and

Fig. 8 is a diagrammatic view showing the turbulence of the combustiblegases in the cylinder during the compression stroke.

Referring to the drawings, the type of internal combustion engine shownembodying this invention is a Diesel engine comprising a cylinder Ihaving a crank case 2 secured thereto. The cylinder I contains acombustion chamber 3 provided with a fuel charge injector 4, an airintake port and an exhaust port 6. The combustion chamber is formed withupperwardly extending curved portions 3a-3a and a centrally locateddownwardly curved portion 3b. A main sleeve piston 1 having a skirtportion 8 of reduced thickness is mounted within the cylinder I andadapted to reciprocate therein. Mounted within the main piston 1 is aninner piston 9, the head of which is provided with a depression I8. Themain sleeve piston 1 and the inner piston 9 are adapted to reciprocatelongitudinally in the cylinder I as well as with respect to one another.

A pair of bearings within the main sleeve piston 1 support a wrist pinII. A connecting rod I2 having a clevis I3 formed in the head thereofengages the wrist pin II and connects the main sleeve piston 1 and acrank shaft I4.

A rocker arm I5 is pivotally mounted on the wrist pin II between thearms of the clevis I3. The rocker arm I5 comprises a verticallyextending portion I6 and a downwardly extending portion I1 which isinclined toward the wall of the cylinder I. The lowermost portion I1 isprovided with a longitudinally extending slot I8, the upper edge ofwhich is slightly rounded at its outer end I9. The vertical portion I8has a drilled oifset 28 to which a clevis 2| formed on the lowermost endof a connecting rod 22 is pivotally connected by a pin 23 extendingthrough an opening formed in the clevis 2| and the drilled opening inthe offset 20. The connecting rod 22 is provided with stop 24 whichbears upon the uppermost horizontal surface of the vertical portion I6when the latter is in a vertical position. The uppermost end of theconnecting rod 2| is pivotally engaged to a wrist pin 25, mounted withinthe inner piston 9. The pistons 1 and 9, the connecting rod 22 and therocker arm I5 are so constructed that the centers of rotation of thelatter two elements about their respective wrist pins 25 and II coincidewith the vertical center line of the sleeve and inner pistons. Thepivotal point 23 between adjacent ends of the connecting rod 22 and therocker arm I5 are beyond dead center with the result that when thevertical portion I6 of the arm I5 is in its uppermost position theseelements assume a fixed relationship and no relative movement betweenthe main sleeve piston 1 and the inner piston 9 occurs.

The skirt 8 of the main sleeve piston 1 is provided with a recess 26which is aligned with plane of rotation of the rocker arm I5. The wallof the cylinder I is provided with an opening 21 which registers withthe sleeve piston recess 26. The cylinder wall opening 21 is adapted toreceive a rocker arm catch 28 which is slldably supported by a bushing29. The innermost end of the catch 28 is bifurcated and provided with a.pin 38 adapted to support a roller 3| between the bifurcated members..The outermost end of the catch 28 is provided with a laterallyextending pin 32 which supports a roller 33. A vertically movablecontrol rod 34 extending from the crank case 2 is provided with anupwardly and outwardly extending angular portion 35 having a slot 36formed therein. The roller 33 of thecatch 28 is positioned within theslot 36 of the angular extension 35. The lowermost end of the controlrod 34 is provided with a roller 31 which engages a cam 38 mounted on ashaft 39. A spring 48 on the control rod 34 is adapted to force thelatter downwardly and into engagement with the com The cam 38 is rotatedand periodically moves the control rod 34 upwardly causing the roller 33on the rocker arm catch 28 to follow the slot 35 in the angularextension duces a periodic reciprocating movement of the rocker armcatch 28. In its innermost position,

the roller 3| between the bifurcated portions of pivotal movement of theconnecting rod 22 and relative longitudinal movement between the mainsleeve piston 1 and the inner piston 9. It will be apparent that, as themain sleeve piston 1 moves downwardly and the rocker arm I5 and thecatch 28 are engaged, the throw of the vertical portion I6 of the rockerarm I5 will cause the inner piston 9 to move downwardly at a greaterrate of speed than that of the sleeve piston 1. At the end of thedownward stroke of the sleeve piston I the inner piston 9 has moveddownwardly within the sleeve piston I, thus providing approximatelyone-third greater volume in the combustion chamber. During the upwardstroke of the sleeve piston 1 the rocker arm I5 and the catch 28 remainengaged producing rotation of the rocker arm in the opposite directionwhich, in turn, causes the inner piston 9 to move upwardly at a greaterrate of speed than that of the sleeve piston. At the end of the upwardstroke of the sleeve piston 1 the rocker arm I5 and the catch 28 aredisengaged and the pivot point 23 between the connecting rod 22 and thevertical portion I8 of the rocker arm I5 passes dead center representedby the center line of the wrist pins I land 25. The inner piston 9 thenfunctions as a head for the main sleeve .piston 1 and relative movementtherebetween does not occur during the power and exhaust strokes. Thecam 38 is designed to provide for progressive engagement anddisengagement of the rocker arm catch 28 with the rocker arm I5 duringthe intake and compression strokes. During the power and exhaust strokesthe rocker arm catch 28 rests in the wall of the cylinder I out ofengagement with the rocker arm I 5 and the latter remains in the overdead center position described with the result that relative movementbetween the main sleeve piston 1 and the inner piston 9 does not occur.

The operating sequence of the engine embodying this invention is showndiagrammatically in Figs. 3 to 7 inclusive. In Fig. 3 the beginning ofthe intake stroke is shown during which phase the main sleeve piston 1has moved downwardly until the roller 3| of the rocker arm catch 28 hasmoved into the slot I 8 of the downwardly extending portion I1 of therocker arm IS. The rotation. of the rocker arm I5 has begun moving thepivot point 23 between the connecting rod 22 and the vertical portion I6from its over dead center position thus causing the inner piston 9 tomove downwardly within the main sleeve piston 1. The movements describedcontinue until the main sleeve piston I and the inner piston 9 reachtheir bottom dead center positions shown in Fig. 4. At this point thevolume of the combustion chamber above the piston will be approximately35. This action proonethird greater than if both pistons had moved as aunit or as would be obtained in engines having a conventional style ofpiston. Accordingly, during the intake stroke an internal combustionengine embodying this invention may introduce at least one-third moreair into the combustion chamber than is possible in the usual form ofinternal combustion engine. The air which is introduced by theconstruction described not only fllls the space in the combustionchamber above piston I, but also the space within the main sleeve pistonI vacated by the inner piston 9. This produces the added advantage ofincreased cooling of the main sleeve piston resulting from the flow ofcool air along the innermost wall of the main sleeve piston.

The compression stroke begins with the movement of the main sleevepiston 1 and the inner piston 9 upwardly from their lowermost deadcenter positions shown in Fig. 4. The rocker arm [5 rotates in theopposite direction as the main sleeve piston I moves upwardly. Therocker arm catch 28 is gradually retracted into the wall of the cylinderl, but remains engaged with the rocker arm l5 until the sleeve piston Iand the inner piston 9 reach their uppermost dead center position shownin Fig. 5. As this point is reached the rocker arm i 5 and the catch 28are disengaged and the pivot point 23 between the connecting rod 22 andthe vertical portion l6 of the arm l5 moves over dead center representedby the center line of the sleeve and inner pistons. The stop Zl rests onthe uppermost horizontal surface of the vertical portion l6 of therocker arm l5 and prevents relative movement between the 'main sleevepiston 1 and the inner piston 9.

During the intake and compression strokes the rocker arm catch 28 ismoved laterally inwardly and outwardly and the roller 3! between thebiiurcated portions of the catch 28 therefore moves inwardly in the slotH! as the intake stroke is performed and outwardly therein as thecompression stroke is accomplished.

The beginning of the powerstroke is shown in Fig. 6. In this cycle ofoperation no relative movement is permitted between the main sleevepiston I and the inner piston 9. The rocker arm catch 28 remains in itsretracted position in the wall of the cylinder I. This relationship isalso maintained during the exhaust stroke shown in Pig. 7. It will beapparent that the increased compression brought about by introducing alarger volume of air during the intake stroke than is obtained byordinary single piston engines will produce more efflcient scavenging ofthe products of combustion formed during the power stroke.

In Fig. 8 a diagrammatic showing indicates the advantage of increasedturbulence of the com bustible gases within the combustion chamberbrought about by the depression In in the head of the inner piston 9 andthe upwardly and downwardly extending curved portions 3a and 31) formedin the uppermost end of the combustion chamber. During the compressionstroke the inner piston 9 moves upwardly with greater speed than themain sleeve piston 1. The depression I 0 tends to direct a concentratedstream of compressed gases on the downwardly extending curved portion3b. As the stream of gas strikes this curved projection it is deflectedinto the up- Iardly curved sections Zia-3a where the direction of flowof the compressed gases is completely reversed and redirected into thestream directed by the depression III. This action continues throughoutthe compression stroke with the result that, at the end of thecompression stroke, the gases have been thoroughly and homogeneouslymixed to provide a uniform mass which facilitates rapid combustion ofthe injected fuel charge.

The invention has been described as applied to a four-stroke Dieselengine, but it is obvious that the invention is equally applicable toall internal combustion engines of the two-cycle and fourcycle type.

Iclaim:

1. An internal combustion engine comprising a working cylinder, 2. mainsleeve piston reciprocating in said cylinder, an inner pistonreciprocating within said sleeve piston, a rocker arm pivotallysupported by said sleeve piston, a connecting rod journaled at oppositeends to said inner piston and said rocker arm, and a reciproeating catchsupported by said cylinder and adapted to engage said rocker arm atpredetermined points in the movement thereof.

2. An internal combustion engine comprising a working cylinder, a mainsleeve piston reciprocating in said cylinder, an inner pistonreciprocating within said sleeve piston, a rocker arm pivotallysupported by said sleeve piston, a connecting rod journaled to saidinner piston and said rocker arm, a reciprocating rocker arm catchsupported by said cylinder, and timing means for moving said catch intoengagement with said rocker arm during the intake and compressionstrokes of said sleeve piston.

3. An internal combustion engine comprising a working cylinder, a crankcase attached to said cylinder, a crank shaft journaled in said crankcase, a main sleeve piston reciprocating in said cylinder, a wrist pinmounted in said main sleeve piston, a connecting rod journaled atopposite ends to said crank shaft and said Wrist pin, an inner pistonreciprocating within said sleeve piston, a rocker arm pivotallysupported by said wrist pin, a connecting rod journaled at opposite endsto said inner piston and said rocker arm, and a reciprocating catchsupported by said cylinder and adapted to engage said rocker arm atpredetermined points in the movement thereof.

4. An internal combustion engine comprising a working cylinder, a crankcase attached to said cylinder, a crank shaft journaled in said crankcase, a main sleeve piston reciprocating in said cylinder, a wrist pinmounted in said main sleeve piston, a connecting rod journaled atopposite ends to said crank shaft and said wrist pin, an inner pistonreciprocating within said sleeve piston, a rocker arm pivotallysupported by said wrist pin, said rocker arm having a vertical extensionand a downwardly depending bifurcated extension, a connecting rodjournaled at opposite ends to said inner piston and said verticalextension of said rocker arm, and a reciprocating catch supported bysaid cylinder and adapted to engage said bifurcated extension of saidrocker arm at predetermined points in the movement thereof.

5. An internal combustion engine comprising a working cylinder, a crankcase attached to said cylinder, a crank shaft journaled in said crankcase, a main sleeve piston reciprocating in said cylinder, a wrist pinmounted in said sleeve piston, a connecting rod journaled at oppositeends to said crank shaft and said wrist pin, an inner pistonreciprocating within said sleeve piston, a rocker arm pivotallysupported by said wrist pin,

said rocker arm having a vertical extension and a downwardly dependingbifurcated extension, a connecting rod Journaled at opposite ends tosaid inner piston and said vertical extension of said RUDOLPH SOL'I'ESZ.

The following refer 8 REFERENCES crran file of this patent:

UNITED STATES PATENTS Number ences are of record in the Name DateZurawski Feb. 19, 1901 Griifith July 15, 1919 Schaeflers July 22, 1919Arbeitel Nov. 6, 1920 Wirrer Nov. 2, 1926 Svete Feb. 5, 1946

